Select-String

A lightweight C wrapper for PowerShell's Select-String cmdlet, providing easy access to PowerShell's powerful text search capabilities from any shell.

Features

• Full PowerShell Select-String support: Access all PowerShell Select-String features
• Regex matching: Supports regular expressions via PowerShell
• Case sensitivity: -CaseSensitive flag support
• File input: Direct file arguments with -Path parameter
• Piped input: Works seamlessly with stdin
• Comprehensive error handling: Validates PowerShell availability and buffer limits
• Windows native: Built for Windows with PowerShell

Requirements

• PowerShell: Must be installed and available in PATH
• Windows: Designed for Windows (uses Windows-specific APIs)
• C compiler: gcc (MinGW/MSYS2) or compatible
• Make: For building from source

Build Commands

# Build the binary
make

# Clean build artifacts
make clean

# Show help
make help

The compiled binary will be placed in bin/Select-String (note: the Makefile creates it without the .exe extension, but it's still a Windows executable).

Installation

# Install to your system PATH
make install

The installer will automatically detect the best location:

• ~/bin (if it exists and is in your PATH)
• /usr/local/bin (on Unix-like systems)
• %SYSTEMROOT%\system32 (on Windows, not recommended)

Manual Installation

If automatic installation doesn't work, manually copy the binary:

cp bin/Select-String ~/bin/
# or
sudo cp bin/Select-String /usr/local/bin/

Make sure the destination directory is in your $PATH.

Usage

This wrapper forwards all arguments to PowerShell's Select-String cmdlet, so you can use any Select-String parameters.

Basic syntax:

Select-String <pattern> [PowerShell Select-String arguments]

Examples

# Search for "error" in piped input
echo "error occurred" | Select-String "error"

# Search files directly with -Path
Select-String "error" -Path *.log

# Case-sensitive search
Select-String "ERROR" -Path app.log -CaseSensitive

# Regular expressions (default)
Select-String "error|warning" -Path *.log

# Search with Get-Content piping
Get-Content app.log | Select-String "critical"

# Complex patterns
Select-String "\d{3}-\d{4}" -Path contacts.txt  # Phone numbers

# Search multiple file types
Select-String "TODO" -Path *.c,*.h

# Context lines (lines before/after match)
Select-String "error" -Path app.log -Context 2,3

Options

# Show help
Select-String --help
Select-String -h

# Show version
Select-String --version
Select-String -v

How It Works

This is a C wrapper that:

1. Detects piped input: Checks if stdin is a pipe using _isatty()
2. Handles piped data: Saves stdin to a temporary file and uses PowerShell's Get-Content to pipe it to Select-String
3. Forwards arguments: Passes all command-line arguments to PowerShell's Select-String cmdlet
4. Calls PowerShell: Executes powershell.exe -NoProfile -Command "...Select-String <args>"
5. Returns output: Streams PowerShell's output back to stdout

Error Handling

The wrapper includes comprehensive error checking:

• PowerShell availability: Validates PowerShell exists in PATH before execution
• Buffer overflow protection: Checks command string doesn't exceed 32,768 bytes
• snprintf validation: Verifies all string formatting operations succeed
• File I/O errors: Validates reads/writes to temporary files
• Pipe errors: Checks for errors reading PowerShell output

Design Philosophy

This wrapper provides:

• Transparent PowerShell access: Full access to PowerShell Select-String features
• Shell integration: Works from bash, PowerShell, or any shell environment
• Simple interface: Just pass arguments as you would to Select-String
• Robust error handling: Comprehensive validation and helpful error messages
• Resource cleanup: Properly manages temporary files and handles

PowerShell Select-String Features

Since this is a wrapper, you get full access to PowerShell's Select-String:

Feature	Supported
Regex patterns	✅ Yes
Case-sensitive matching	✅ Yes (-CaseSensitive)
File path patterns	✅ Yes (-Path)
Context lines	✅ Yes (-Context)
Line numbers	✅ Yes (in output)
Simple matching	✅ Yes (-SimpleMatch)
Multiple patterns	✅ Yes (via regex)
Recursive search	✅ Yes (use Get-ChildItem with piping)

Building from Source

The build system uses:

• Compiler: gcc (MinGW/MSYS2 recommended)
• Flags: -std=c99 -Wall -Wextra -Wpedantic -O2 -DNDEBUG
• Output: bin/Select-String (Windows executable)
• Binary size: ~240KB

Technical Details

• Uses Windows-specific APIs: _isatty(), _popen(), _tempnam()
• Command buffer: 32,768 bytes
• Data buffer: 8,192 bytes
• Temporary file handling for piped input

Uninstalling

make uninstall

Or manually remove the binary from your PATH.

License

This is free and unencumbered software released into the public domain.

Contributing

This is a personal utility tool, but feel free to fork and modify as needed.

Why This Exists

This wrapper makes PowerShell's Select-String easily accessible from any shell environment (bash, cmd, etc.) without needing to write PowerShell syntax. It handles the complexity of:

• Detecting and managing piped input
• Properly escaping and formatting PowerShell commands
• Managing temporary files for stdin data
• Providing helpful error messages
• Cleaning up resources

You get the power of PowerShell's regex-enabled search with the simplicity of a traditional command-line tool.

Limitations

• Windows only: Uses Windows-specific APIs
• Requires PowerShell: Must have PowerShell installed and in PATH
• Command length: Limited to 32,768 bytes for the command string
• Startup time: Includes PowerShell startup overhead (typically ~100-200ms)